Animal song

[2] Song-like productions have been identified in several groups of animals, including cetaceans (whales and dolphins), avians (birds), anurans (frogs), and humans.

[3] Although morphological differences between species affect production of sound, neural control is thought to be more essential factor in producing the variations within human speech and song compared to those of other mammals.

[4] Sound vibrations are conveyed to an organ in the head called the melon, which can be changed in shape to control and direct vocalizations.

[3] However, frogs also use structures called vocal sacs, elastic membranes in the base of the mouth which inflate during sound production.

[7] These sacs provide both amplification and fine-tuning of sounds, and also allow air to be pushed back into the lungs during vocalizations.

[7] Increased efficiency of sound production is important, as some frogs may produce calls lasting for several hours during mating seasons.

[7] The New River tree frog (Trachycephalus hadroceps), for example, spends hours producing up to 38,000 calls in a single night, which is made possible through the efficient recycling of air by the vocal sac.

[8] The primary vocal organ of birds is called the syrinx, which is located at the fork of the trachea, and is not present in mammals.

[9] Insects such as crickets (family Gryllidae) are well known for their ability to produce loud song, however the mechanism of sound production differs greatly from most other animals.

[15][16] Locusts and other grasshoppers (suborder Caelifera) stridulate by rubbing hind legs against pegs on wing surfaces in an up and downward motion.

[17] Cicadas (superfamily Cicadoidea) produce sound at much greater volumes than orthopterans, relying on a pair of organs called tymbals on the base of the abdomen behind the wings.

[19] For example, many frogs may use trilling notes in mate attraction, but switch to different vocal patterns in aggressive territorial displays.

[19][22] For eastern smooth frogs (Geocrinia victoriana), for example, courtship songs involve shorter notes to attract potential mates, and are followed by longer tones to repel males.

[22] In great tits (Parus major), nightingales (Luscinia megarhynchos), blackbirds (Turdus merula) and sparrows (family Passeridae), playing song recordings slows the rate at which males establish territories in an unoccupied region, suggesting these birds rely on song output in establishing territorial boundaries.

[22] Experimentally muted Scott's seaside sparrow (Ammodramus maritimus) lose control of their territories to other males.

[28] Cliff swallows (Petrochelidon pyrrhonota) have been demonstrated to preferentially respond to parental songs at a young age, providing a means of vocalization-based offspring recognition.

During the sensorimotor phase, young birds initially produce variable, rambling versions of adult song, called subsong.

[34] The sensitive period in which birds must be exposed to song tutoring varies across species, but typically occurs within the first year of life.

[31] Although birds are capable of learning song production purely from audio recordings of birdsong, tutor-student interaction may be important in some species.